61620221 has 8 divisors (see below), whose sum is σ = 66699864. Its totient is φ = 56589120.

The previous prime is 61620199. The next prime is 61620227. The reversal of 61620221 is 12202616.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 36168196 + 25452025 = 6014^2 + 5045^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61620221 - 2¹⁰ = 61619197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61620193 and 61620202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61620227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9470 + ... + 14591.

It is an arithmetic number, because the mean of its divisors is an integer number (8337483).

Almost surely, 2^61620221 is an apocalyptic number.

It is an amenable number.

61620221 is a deficient number, since it is larger than the sum of its proper divisors (5079643).

61620221 is a wasteful number, since it uses less digits than its factorization.

61620221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24271.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 61620221 is about 7849.8548394222. The cubic root of 61620221 is about 394.9793740231.

Adding to 61620221 its reverse (12202616), we get a palindrome (73822837).

The spelling of 61620221 in words is "sixty-one million, six hundred twenty thousand, two hundred twenty-one".